Piezoelectric device and process for production thereof

Abstract

A sheet-form piezoelectric device having improved mechanical strengths as represented by an electrode peel strength while retaining flexibility and piezoelectric performances of a polymer-type piezoelectric device, is obtained by embedding a perforated sheet electrode into at least one surface layer of a polymer piezoelectric film treated with a solvent in advance. The sheet-form piezoelectric device may be wound or curved about a certain central axis to provide a tubular or curved piezoelectric device having wave-transmitting and/or -receiving characteristics suitable for wave-transmitting and/or -receiving devices, such as a hydrophone and microphone.

What is claimed is: 
     
       1. A sheet-form piezoelectric device, comprising: a polymeric piezoelectric film or sheet, and a perforated sheet electrode embedded within at least one surface layer of the piezoelectric film or sheet; wherein   (a) said polymeric piezoelectric film or sheet has a thickness of 50-2000 μm, and   (b) said perforated sheet electrode is (i) a mesh electrode having a perforation of 20-350 μm and a wire diameter of 20-300 μm, or   (ii) a bored plate electrode having a thickness of 10-800 μm and an areal opening ratio of 10-70%.     
     
     
       2. The tubular piezoelectric device, comprising: a sheet-form piezoelectric device formed by embedding a perforated sheet electrode within a surface layer of a polymer piezoelectric film or sheet, and wound around a certain central axis into a tube, and wherein:   (a) said polymeric piezoelectric film or sheet has a thickness of 50-2000 μm, and   (b) said perforated sheet electrode is (i) a mesh electrode having a perforation of 20-350 μm and a wire diameter of 20-300 μm or   (ii) a bored plate electrode having a thickness of 10-800 μm and an areal opening ratio of 10-70%.     
     
     
       3. The tubular piezoelectric device according to claim 2, wherein the sheet-form piezoelectric device is provided with an insulating coating at least one surface thereof and is wound in plural turns around the central axis into a tube with plural superposed layers of the sheet-form piezoelectric device. 
     
     
       4. A curved piezoelectric device, comprising: a sheet-form piezoelectric device formed by embedding a perforated sheet electrode within a surface layer of a polymer piezoelectric film or sheet, and formed into a curved shape with respect to a certain central axis, and wherein:   (a) said polymeric piezoelectric film or sheet has a thickness of 50-2000 μm, and   (b) said perforated sheet electrode is (i) a mesh electrode having a perforation of 20-350 μm and a wire diameter of 20-300 μm or   (ii) a bored plate electrode having a thickness of 10-800 μm and an areal opening ratio of 10-70%.